What is the best description of resonance?

Correct Answer: A

Rationale: Resonance refers to the quality of sound produced by vibrations that are reinforced by other vibrations of the same frequency. In the context of the human body, resonance is often associated with sounds produced by air-filled structures like the lungs, vocal cords, and resonating cavities. Therefore, the best description of resonance from the given options is 'Sounds created by air-filled lungs.' This choice aligns with the concept of resonance as it relates to sound production in the human body.

Correct Answer: A

Rationale: Gait is the correct answer because it specifically describes the pattern of movement of the limbs during locomotion, particularly walking or running. It encompasses the rhythm, speed, and coordination of steps, as well as the biomechanics involved in maintaining balance and propulsion. Gait analysis is a critical component in fields like physical therapy, orthopedics, and neurology to assess normal and pathological movement patterns. The term is precise and universally recognized in medical and anatomical contexts to describe the way a person walks. Range of motion (B) is incorrect because it refers to the extent of movement a joint can achieve, such as bending or rotating, rather than describing the act of walking itself. While range of motion is important for mobility, it is a measure of joint flexibility and not synonymous with gait. For example, a person with limited hip range of motion may have an altered gait, but the two terms are distinct concepts. Flexion and extension (C) are incorrect as they describe specific types of joint movements rather than the overall manner of walking. Flexion refers to decreasing the angle between two bones (e.g., bending the knee), while extension refers to increasing that angle (e.g., straightening the knee). Although these movements contribute to walking, they are individual components of locomotion and do not encapsulate the coordinated sequence of steps that define gait. Hopping (D) is incorrect because it is a specific type of locomotion involving a single-leg takeoff and landing, which is fundamentally different from walking. Walking requires alternating steps between both legs with at least one foot always in contact with the ground, whereas hopping is a unilateral, ballistic movement. While hopping is a form of movement, it does not describe the general manner of walking, making it an unsuitable answer for this question. The distinction between these terms is crucial for understanding human movement. Gait is the overarching concept that integrates multiple biomechanical elements, while the other choices represent narrower or unrelated aspects of motion. Mastery of these definitions ensures clarity in medical, athletic, and rehabilitative contexts where precise terminology is essential.

Correct Answer: A

Rationale: The Snellen chart is a standardized tool used to assess visual acuity, which is the clarity or sharpness of vision. This directly involves the optic system, specifically the optic nerve (cranial nerve II), which transmits visual information from the retina to the brain. The optic nerve is responsible for carrying visual stimuli, and the Snellen chart measures how well this system functions by determining the smallest letters a person can read at a standardized distance. This makes **A (Optic)** the correct answer, as the test evaluates the integrity and performance of the optic pathway, including the retina, optic nerve, and visual processing centers in the brain. **B (Olfactory)** is incorrect because the olfactory system pertains to the sense of smell, mediated by the olfactory nerve (cranial nerve I). The Snellen chart has no relevance to smell, as it is purely a visual assessment tool. There is no overlap between testing visual acuity and evaluating olfactory function, which would instead involve identifying scents. **C (Oculomotor)** is incorrect because while the oculomotor nerve (cranial nerve III) controls most eye movements (such as upward, downward, and medial gaze) and pupil constriction, it does not play a direct role in visual acuity. The Snellen chart primarily tests the ability to discern letters, not eye movement coordination or pupillary reflexes, which would be the focus of oculomotor nerve assessment. **D (Trochlear)** is incorrect because the trochlear nerve (cranial nerve IV) is responsible for the movement of the superior oblique muscle, which allows the eye to look downward and inward. Like the oculomotor nerve, its function relates to eye movement rather than visual acuity. Testing with the Snellen chart does not assess the trochlear nerve’s role in ocular motility, making this choice irrelevant in this context. The question assesses whether the student understands the anatomical and functional distinctions between cranial nerves. The Snellen chart is a straightforward test of the optic system, and the distractors (B, C, D) represent nerves with unrelated roles (smell and eye movement), ensuring that the correct choice reflects an understanding of visual pathway evaluation. Misidentifying the correct nerve could indicate confusion between sensory (optic) and motor (oculomotor, trochlear) functions of the cranial nerves or misunderstanding the specific purpose of the Snellen chart. A strong grasp of these distinctions is crucial for clinical assessments involving vision and neurological function.

Correct Answer: B

Rationale: The knee-chest position is correctly identified as the genu-pectoral position. In this position, a person rests on their knees and chest with the abdomen raised and the head turned to one side. This position is commonly used in medical examinations and procedures involving the rectal or pelvic areas, allowing for better visualization and access.

Correct Answer: D

Rationale: The Z-track technique is the best action to prevent tracking of the medication when administering an IM injection that is irritating to the subcutaneous tissue. This technique involves pulling the skin to the side before administering the injection and then releasing the skin after the injection. By doing so, a zig-zag pathway is created, preventing the medication from leaking into the subcutaneous tissue and reducing irritation.